This invention relates in general to electrical transformers having laminated metal cores, and more particularly to an internal cooling arrangement for the cores of such transformers.
In high frequency induction heating operations, stationary transformers are employed which must be capable of handling extremely high electrical currents. It is a well recognized requirement for such transformers that the parts thereof such as the metal core be cooled as by water-cooling in order to remove the heat generated in the transformer during operation. While the present invention is particularly applicable to a transformer of this type, it is, of course, not limited to this particular application and may be employed in any type of transformer that requires liquid-cooling of the transformer core.
In transformers of the above referred to type having a water-cooled core, such as shown for example in U.S. Pat. No. 2,655,636, and having a core made up of a stack of a plurality of relatively flat and thin laminations formed from a magnetically permeable material such as iron, for instance, the core laminations are commonly interleaved, at spaced regions throughout the core thickness, by a plurality of correspondingly shaped cooling laminations formed of copper or other high heat-conducting material which have flat thin tubes of copper or other high heat conductive material brazed or soldered along edges of the laminations, through which tubes a cooling medium may be circulated. Such metallic type core cooling members, however, effect only minimal cooling of the core by the cooling medium circulated therethrough during transformer operation and they are characterized by high material cost as well as fabricating cost. In addition, they inherently produce objectionable circulating eddy currents within the core such as add to the heat generation therein during transformer operation.